Attaching Basement Ceiling Rim Joist to Concrete Walls

Moved by sharward from Is a Floating Floor Right For You? Answer: Probably NOT... Great post - thanks so much. It actually spurred me on to my very first post.... If you don't use a floating floor in a basement, how about the basement's ceiling, independent of the floor above? Are there methods of attaching the basement ceiling's rim joist to the basement's concrete walls that are preferred? I was going to attach 2x10s straight to the concrete walls with soley a layer of roofing felt (for moisture protection) but maybe another "layered sandwich" is preferred for flanking noise? Again, not touching the floor joists above. Please forgive me if this is a hijacking - I'll glady go where I'm told! The slab discussion was dead-on.

Not to sound stupid, but since this was moved from another thread, is there any additional info that's needed for a response? Thanks

Your ceiling design really doesn't depend on your floor design. Yes, there are ways to decouple the ceiling below from the floor above. From worst to best: Resilient Channel ("RC"), Resilient Channel Isolation Clips ("RSIC"), or ideally, if you can afford the clearance, separate joists firmly attached to the new inner leaf walls. Have you bought Rod's book yet? Have you read the "Before You Post" announcement, and followed through to the critically important "Reference Area" thread? Have you looked at some of the prominent basement conversion threads that are pretty active right now? All of the above will go very far towards giving you the education you'll need to come up with a workable plan. :-) I hope that gets you started on some fine reading/research material. --Keith :mrgreen:

Thanks Sharward, Yes I have, but the book's not here in Nashville anywhere (I've looked!). My basement's concrete walls and floor are all poured and attached together - a typical residential basement in the Southeastern US. For the new basement ceiling a new rim joist would go around the enitre basement wall's perimeter, below the upper floor (and not touching, either), and the new ceiling joists would attach here. So the decoupling from the upper floor is resolved. As per the Do You Need A Floating Floor Thread, I was wondering about methods for attaching this new ceilng rim joist to the existing concrete basement walls. Many discussions reference new inner leaf walls, but no one's mentioned use of the existing underground concrete walls. To say it all another way, if you're finishing off a basement, is there any method to decouple the ceiling from the walls that support it. And if not, any methods to attenuate flanking noise? Sincerest thanks and appreciation for responding, Mark

Hey Mark,

mlange wrote:

Yes I have, but the book's not here in Nashville anywhere (I've looked!).

Just follow this link, and then the link within that initial post... You can buy it on Amazon.com.

mlange wrote:

For the new basement ceiling a new rim joist would go around the enitre basement wall's perimeter, below the upper floor (and not touching, either), and the new ceiling joists would attach here. So the decoupling from the upper floor is resolved.

No, it's not. :roll: By fastening the lower ceiling to rim joists that are firmly attached to the basement walls, you would have a pretty bad flanking path. The firm attachment of rim joists to the existing concrete walls is, in my opinion, a non-starter. Ideally you would do "room in room," building new wall frames and attaching them to the floor of your basement, and then installing ceiling joists firmly attached to the top plates of your new wall frames. If you leave enough of a gap between new frames and existing concrete walls, you wouldn't even need any resilient sway braces. In my last post I asked: "Have you looked at some of the prominent basement conversion threads that are pretty active right now?" Whose threads have you looked at so far? (This is a quiz! ;-)) Rod's book will go a long way towards clearing this stuff up for you. 8) --Keith :mrgreen:

Thanks Keith, In both Marc and Arron's case they were able to take different approaches than I. 1- As my basement is below ground 2- and there are a "1000 hands" supporting the floor 3- why wouldn't the "1000 hands" of dirt and rock provide damping for my walls as well? I've built two other studios as you describe (room w/in a room; staggered studs; good modal balance and room ratios), but this new pursuit has limitations. The new ceiling will be 2 layers of 5/8" drywall with a Green Glue sandwich. If there are treatments for the rim joists, I'd employ them, too. Cheers! Mark thanks for the Amazon link!!

mlange wrote:

In both Marc and Arron's case they were able to take different approaches than I.

Marc who? (If you're talking about guitardad72, his is not a basement...)

mlange wrote:

I've built two other studios as you describe (room w/in a room; staggered studs; good modal balance and room ratios) . . .

Point of clarification: I never described staggered studs. Staggered studs tend to suck. :x

mlange wrote:

The new ceiling will be 2 layers of 5/8" drywall with a Green Glue sandwich. If there are treatments for the rim joists, I'd employ them, too.

Do you not have the vertical clearance to allow for a separate ceiling frame? (Don't answer that until you have Rod's book and read about his interleaved joist concept in Chapter 4.) --Keith :mrgreen:

My bad on Marc - and as well on the staggered studs. I've built two room-within-a-room configs & staggered studs have performed well in the past for me. I do have ample vertical room for a separate ceiling frame. It 's this exact rim joist for which I am speaking. Specifically between it and the concrete walls. There will be a separate ceiling frame throughout. Thanks, Mark

You don't need to attach an inner frame ceiling rim joist to an outer leaf concrete wall at all. Just pretend the outer leaf wall isn't there... Like you're building a shed that happens to be a little smaller than the basement. No sway beaces, no anchoring to outer leaf walls. You'll need fire stops though... See my thread's inner leaf framing pages for details. It's really similar to my inner leaf framing... Except that mine's above ground and yours is underground. --Keith :mrgreen: